You currently have javascript disabled. Several functions may not work. Please re-enable javascript to access full functionality.

Welcome to Ultimate Subaru Message Board, my lurker friend!

Welcome to Ultimate Subaru Message Board, an unparalleled Subaru community full of the greatest Subaru gurus and modders on the planet! We offer technical information and discussion about all things Subaru, the best and most popular all wheel drive vehicles ever created.

We offer all this information for free to everyone, even lurkers like you! All we ask in return is that you sign up and give back some of what you get out - without our awesome registered users none of this would be possible! Plus, you get way more great stuff as a member! Lurk to lose, participate to WIN*!

Say hello and join the conversation

Subscribe to topics and forums to get automatic updates

Get your own profile and make new friends

Classifieds with all sorts of Subaru goodies

Photo hosting in our gallery

Meet other cool people with cool cars

Seriously, what are you waiting for? Make your life more fulfilling and join today! You and your Subaru won't regret it, we guarantee** it.

* The joy of participation and being generally awesome constitutes winning** Not an actual guarantee, but seriously, you probably won't regret it!

Ok,
Does no one have the answer to this? Has no one else encountered this? Have I stated it so you don't understand the question? Or is this such a tired, rehashed question that no one wants to go over it again?

Apologies, it is a true Hatchback with the EA81, CA specs $hitachi carb, d/r 4spd.

I understand that the weber is the best option and is on the long list of "to-do's", but i just would like to know what the Ignition Pulse System is all about and why i'm getting the 73 code thrown at me.

There isn't much on the EA81 as far as electrical or electronic components. The ECM is there to control and monitor the emissions isn't it? Aside from the distributor, and coil there isn't much else to the ignition like other cars. CPS, MAP, MAF, etc are not there. Does your tach jump around? Have you tuned it up latley? New plugs, wires, cap and rotor? Get a repair manual and test the coil and distributor. I would bet it's the disrtributor. Does it have the NipponDenso or Hitachi distributor? It will say on the unit.

Does your tach jump around? Have you tuned it up latley? New plugs, wires, cap and rotor? Get a repair manual

It has been completely tuned in the last 3k miles but has been bucking and running a little rough lately. And, actually, the tach has been jumping around erratically lately. I'd have to agree that the disty is on it's last leg, but assumed that was a separate issue than the code 73.

The codes are specific to the vehicle type - 73 indicates a fualt on a Hitachi carbed, analog gauge cluster, california manual transmission vehicle. Being you are in Nevada that makes sense - your car was sold in CA and as such it's a feedback even though it's 4WD. (49-states 4WD's were not).

The problem with that code is that it's a general fault code - there's about 20 pages of troublshooting that you have to go through to trace that code, and it will probably end up being a corroded connector, faulty splice, or the ECU itself (leaky caps, or something perhaps). It could take DAYS of troubleshooting to find it.

IE: I wouldn't worry about that code. Fix your distributor first, and then if you still have that code.... yard that ECU out of the car and install a normal non-feedback Hitachi or a Weber.

Actually there are two duty-control solenoids that modify airflow to three metering ports on the carb. The ECU has enough control through these to cause the engine to die at an idle or to run very badly if the O2 or CTS have gone south.

The ECU cannot directly modify the ignition timing, that's true. But it does have lines used to monitor ignition pulses from the coil.

The codes are specific to the vehicle type - 73 indicates a fualt on a Hitachi carbed, analog gauge cluster, california manual transmission vehicle. Being you are in Nevada that makes sense - your car was sold in CA and as such it's a feedback even though it's 4WD. (49-states 4WD's were not).

The problem with that code is that it's a general fault code

Actually, 73 is an Identifier code.

There is no Flow chart or any other troubleshooting info is in the FSM for codes 11,71,72,73 because they are ID codes presented when the key's ON/Eng OFF. (respective to Cali/fed 2wd/4wd)

If the CEL is on while driving and 73 is the only code, then the ECU is not seeing the ignition pulse that should be from the Negative side of the coil, to the ECU. It's not a *fault*, so much as just the ECU thinking the car is not running because it see's no pulse.

Jumpering a wire from the Neg of the Coil to the pin on the ECU should serve to bypass the original wire. Sorry, I don't have the ECU pinout here, but search or PM me for info later.

There is no Flow chart or any other troubleshooting info is in the FSM for codes 11,71,72,73 because they are ID codes presented when the key's ON/Eng OFF. (respective to Cali/fed 2wd/4wd)

Well - the way I read the FSM it shows it as an identifier, but also says (in the flow matrix) "the subsequent check is continued" - ie: you should continue troubleshooting straight through the lettered tests from where you stopped when it told you to check for codes (and you came up with a 73).

If the CEL is on hile driving and 73 is the only code, then the ECU is not seeing the ignition pulse that should be from the Negative side of the coil, to the ECU. It's not a *fault*, so much as just the ECU thinking the car is not running because it see's no pulse.

Now that I have not seen stated anywhere in my FSM. You may be correct.... and in fact it does sound right maybe..... damn these FSM's are confusing! There's a lot of ways you can interpret it. If you run through all the detailed flow charts starting from the top we might be able to infer what the code is - but half the time the checks themselves are ambiguously worded so that you aren't even sure you passed or failed the check

Jumpering a wire from the Neg of the Coil to the pin on the ECU should serve to bypass the original wire. Sorry, I don't have the ECU pinout here, but search or PM me for info later.

If he has to do that though..... that's a sign of bigger problems. If that wire isn't connected there's a bad spot in a harness somewhere. Bad juju.